1. Field of the Invention
The present invention relates to a maximum power point tracker that can be mounted in a solar cell module or is applicable to a module integrated converter (MIC), a power conversion device having an insulating structure, and a method for controlling a maximum power point, and more particularly, to a maximum power point tracker capable of performing a maximum power operation by using a current value in a DC/AC converter without having to detect a voltage value and being thus able to be fabricated at a low cost, a power conversion controller, a power conversion device having an insulating structure, and a method for tracking the maximum power point.
2. Description of the Related Art
In general, a solar power generation system may include a solar cell array including a plurality of solar cells connected in series or parallel to each other, and a power conversion device for a single solar generation system.
The power conversion device, operating the solar cell array such that the solar cell array generates an output at a maximum power point, converts a DC output of the solar cell array into an AC output and provides it to an electrical power system.
Here, even in the case that the solar cell modules are of the same model, they may have different output characteristics, and also, if the overall solar cell array is not irradiated with the uniform level of solar irradiation, the respective solar cell modules constituting the solar cell array would fail to generate maximum power they can, resulting in a reduction in an overall energy conversion efficiency of the solar generation system.
Thus, in order to solve the problem, the solar generation system may include a plurality of small capacity DC/DC converters mounted at the plurality of solar cell modules and a large capacity DC/AC power converter converting DC electricity from the plurality of small capacity DC/DC converters into AC electricity.
In this case, the small capacity DC/DC converters control the tracking of a maximum power point, respectively, to allow the plurality of solar cell modules to generate maximum power. Namely, the plurality of solar cells can be operated at a maximum power point, respectively.
In this case, such a solar generation system basically requires a voltage detector and a current detector for calculating power in order to track the maximum power point.
Also, in order to improve the shortcomings of the related art solar generation system, the solar generation system may include a plurality of DC/AC power converters mounted at the plurality of solar cell modules, respectively.
In such a system, power generated from the plurality of solar cell modules may be directly converted into system power so that the plurality of solar cell modules can operate at the maximum power point.
Then, in the foregoing solar generation system, because the plurality of solar cell modules operate at the maximum power point, respectively, and are directly associated with the commercial electric power system without using a large capacity DC/AC power machine, high-priced DC wiring is not necessary.
In this case, such a solar generation system basically requires a voltage detector and a current detector for calculating power in order to track the maximum power point.
However, in the related art solar generation system, if the quantity of solar energy irradiated to the solar cell array is not the same or when each solar cell module has different characteristics due to a problem in terms of fabrication, the solar cell modules cannot operate at the maximum power point.
In addition, the related art solar generation system requires a large number of sensors. Namely, if N number of solar cell modules are required to constitute the over solar generation system, a total of four sensors, two for an input side and the other two for an output side, would be required for each solar cell module, resulting in the situation that the number of sensors required for the overall solar generation system is 4*N. Thus, because a large amount of sensors are required, the fabrication cost increases.